#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=1e5+1000;
typedef long long LL;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
LL a[maxn];
bool cmp(LL A,LL B){
    return A>B;
}
map<LL,LL>map1;
int main(void)
{
  	cin.tie(0);std::ios::sync_with_stdio(false);
    LL t;cin>>t;
    while(t--){
        LL n,w;cin>>n>>w;
        map1.clear();
        for(LL i=1;i<=n;i++) cin>>a[i],map1[a[i]]++;
        LL cnt=1;
        LL h=0;
        map<LL,LL>::reverse_iterator rit;
        while(cnt<=n){
            LL temp=w;
            for(rit =map1.rbegin();rit!=map1.rend();rit++){
                while(rit->second>=1&&rit->first<=temp){
                    map1[rit->first]--;
                    temp-=rit->first;
                    cnt++;
                }
            }
            h++;
        }
        cout<<h<<"\n";
    }
return 0;
}
